US20020173212A1

US20020173212A1 - Nonwoven material

Info

Publication number: US20020173212A1
Application number: US09/860,975
Authority: US
Inventors: David Wenstrup
Original assignee: Milliken and Co
Current assignee: Milliken and Co
Priority date: 2001-05-18
Filing date: 2001-05-18
Publication date: 2002-11-21
Also published as: US20040087236A1; WO2002094554A1

Abstract

A nonwoven material which is formed of a blend of fibers diagonally needled together into an integral web for subsequent molded component parts.

Description

BACKGROUND

The present invention generally relates to nonwovens, and in particular, to nonwovens that are subsequently molded into an article, such as a headliner for automobiles.

Current processes for forming nonwovens with rigidity for subsequent articles, such as automobile headliners, uses fiberglass to get the necessary rigidity for the construction. However, the use of fiberglass requires special handling requirements. Therefore, there is a need for nonwoven materials which can eliminate fiberglass and provide the necessary construction rigidity for applications such as automotive headliners. In the past elimination of the fiberglass resulted in an increase of the nonwoven weight and raw material cost. Thus a need remains for nonwoven materials having high rigidity, reduced weight and raw materials, and the elimination of special handling requirements.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, reference should be made to the following drawings in conjunction with the detailed description below: [0003]
FIG. 1 is a perspective view of a nonwoven material of the present invention.[0004]

DETAILED DESCRIPTION

The present invention generally relates to nonwoven materials which are formed of a blend of fibers needled together into an integral web for subsequent molding into component parts. Referring now to the figures, and in particular to FIG. 1 there is shown an embodiment of the present invention illustrated as the nonwoven [0005] 10, formed of staple fibers 11. The nonwoven 10 has a length direction x, a width direction y, and a thickness direction z. The x direction is typically the machine direction, the y direction is typically the cross machine direction, and the z direction is typically the thickness of the nonwoven 10.
It is preferred that the blend of fibers [0006] 11 forming the nonwoven 10 include synthetic polymeric fibers. In one embodiment, the fibers 11 forming the nonwoven 10 include a combination of low melt semi-crystalline polyester sheathed fibers and higher melting polyester fibers. The low melt sheathed polyester fibers have a sheath melting point of from about 130° C. to about 165° C. The fibers 11 are typically from about 1 to about 20 denier per filament (DPF), and in one embodiment, the fibers are from about 3 to about 18 DPF. Staple length of the fibers 11 is typically from about 1 to about 4 inches in length, and in one embodiment, are from about 1.5 to about 3.0 inches in length.
In one embodiment of forming the present invention, the combination of fibers [0007] 11 are blended in a card, and layered as a web on a belt by a cross lapper. Once layered on the belt, the web of blended polyester fibers 11 is needled at an angle from the z direction of the web in the x-z plane, to lock the fibers 11 together into the integral batting of the nonwoven 10. The web can be needled at an angle of from about 30° to about 60° from the z-axis. In one embodiment, the web is needled at about a 45° angle to the z-axis. The angled needling is usually done in addition to the standard needling, performed parallel to the z axis. By needling the web at an angle from the z-axis in the x-z plane, the nonwoven 10 obtains a greater rigidity to resist sagging in the z axis along the x direction of the nonwoven 10 over webs having a comparable fiber content. It has also been discovered that the use of diagonal needling can allow a reduction in the overall amount of polyester fibers necessary for the same strength nonwoven web, and correspondingly for the same strength molded component part.
Component parts formed from the nonwoven [0008] 10 can be molded into a desired shape by applying temperature and pressure to the component part. The temperature and pressure of the molding process causes the low melt sheath of the low melt sheath fibers to melt and fuse with the high melt fibers and the other low melt sheath fibers. An unexpected result of the present invention, is that an increase in the strength of the nonwoven component part due to angled needling, actually resulted in a greater percentage increase in strength of the molded part than was noticed in the pre-molded nonwoven component part.
Molded parts formed from the nonwoven [0009] 10 with the angled needing experience an increased rigidity, giving an increase resistance to sagging. A component part that has been molded from the nonwoven 10 with the angled needling of the present invention, such as an automotive headliner, can obtain an increased rigidity that resists sagging of the nonwoven 10 in the z axis along the x direction on the order of about 25%. Additionally, the nonwoven 10 formed into the component part of an automotive headliner can be rotated to about a 90° angle around the z axis, allowing the x-axis to run essentially across the car, rather than fore-aft. This angled rotation of the nonwoven 10 can improve manufacturing of component parts by facilitating nesting of the component parts in the nonwoven 10 in a manner that takes advantage of the increased rigidity of the nonwoven 10 in the x direction.

Claims

What is claimed is:

1. A nonwoven formed from a plurality of fibers needled into an integral web having an x-axis, an y-axis, and an z-axis, wherein said fibers are needled at an angle from the z axis in the x-z plane, and wherein the fibers forming said nonwoven include low melt semi-crystalline polyester sheath fibers and higher melt polyester fibers.

2. The nonwoven according to claim 1, wherein the angle that the fibers are needled is from about 30 to about 60° from the z-axis.

3. The nonwoven according to claim 1, wherein the angle that the fibers are needled is about 45° from the z-axis.

4. The nonwoven according to claim 1, wherein the fibers forming said nonwoven comprise synthetic polymeric fibers.

5. The nonwoven according to claim 6, wherein the sheath of the low melt semi-crystalline polyester sheath fibers has a melting point of from a bout 130° C. to about 165° C.

6. The nonwoven according to claim 1, wherein the fibers forming the nonwoven comprise fibers having a denier per filament of from about 1 to about 20.

7. The nonwoven according to claim 1, wherein the fibers forming the nonwoven comprise fibers having a denier per filament of from about 3 to about 18.

8. The nonwoven according to claim 1, wherein the fibers forming the nonwoven comprise fibers having a staple length of from about 1 inches to about 4 inches.

9. The nonwoven according to claim 1, wherein the fibers forming the nonwoven comprise fibers having a staple length of from about 1.5 inches to about 3.0 inches.

10. The nonwoven according to claim 1, wherein the fibers forming the nonwoven are also needled parallel to the z axis.

11. A method of forming a nonwoven comprising the steps of:

blending a plurality of core/sheath fibers with a plurality of matrix fibers;

layering a web of the blended fibers into a planar shape having an x-axis, an y-axis, and an z-axis;

needling the web of fibers at an angle to the z-axis in the x-z plane such that an integral mat is formed.

12. The method according to claim 11, wherein the step of needling the web of fibers at an angle includes the angle being from about 30° to about 60° from the z-axis in the x-z plane.

13. The method according to claim 11, wherein the step of needling the web of fibers at an angle includes the angle being about 45° from the z-axis in the x-z plane.

14. The method according to claim 11, wherein the step of needling the web of fibers includes also needling the fibers substantially parallel to the z axis of the web.

15. The method according to claim 11, wherein the sheath of the core/sheath fibers comprise a low melt semi-crystalline polyester.

16. The method according to claim 15, further including the step of molding the needled web of fibers into a molded component part with the application of heat and pressure.